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Thread: Advice about what to do with bolt holes in concrete floor

  1. #1
    Join Date
    Nov 2004
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    Staunton, Virginia
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    379

    Advice about what to do with bolt holes in concrete floor

    We just purchased a new shop building that was previously a body shop.

    As you can see from the attached picture there are many (173 to be exact) bolts protruding from the concrete.

    Floor Bolts.JPG


    Getting them out has been tedious work, however it is coming along OK.

    My question is about what would be the best way to fill the holes left behind. Has anyone encountered anything similar?

    Thanks in advance for the advice.

    Rick Hubbard

  2. #2
    Join Date
    Mar 2003
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    I have some similar depressions in my shop floor from removing a wall...my plan is to (finally) patch with just mortar.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  3. #3
    Join Date
    Feb 2008
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    E TN, near Knoxville
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    Quote Originally Posted by Rick Hubbard View Post
    As you can see from the attached picture there are many (173 to be exact) bolts protruding from the concrete.
    I cut them off just below flush with an abrasive disk on a 4-1/2" angle grinder then patch the slight depression.

    JKJ

  4. #4
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    Apr 2016
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    Cut them off just below or flush with the surface and patch with epoxy. Pulling them out is paying for work that doesn't need to be done. Fill the ones you have pulled out with a cement based patch mortar. Remember it is a factory floor and it will not make a single extra dollar by removing every bolt when simple cutting does the same job. I move machinery a lot and cutting flush is still good 20 years later. Cheers

  5. #5
    Join Date
    Sep 2016
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    Modesto, CA, USA
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    After I drilled my sidewalk, to inject termite killer, I plugged the hole with some dense foam then shot a little self leveling concrete patch in a calking gun to fill each hole.
    BTW do you have a hollow ram hydraulic cylinder to pull those out or are you unscrewing them?
    Bil lD

  6. #6
    Join Date
    Feb 2003
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    Griswold Connecticut
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    I'm with John

    BTDT.
    Grind then off flush or slightly below and patch with an anchoring cement.
    The other option is to drill a bigger hole around them and remove them that way.
    I wouldn't keep pulling them out. Those are wedge type, drop in, anchors,and the way that they are positioned, in a line, as you remove them,the wedges may start to create a seam crack along the line.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  7. #7
    Join Date
    Dec 2006
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    Toronto Ontario
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    I always drill the hole deeper than the anchor.

    If you're lucky so did the person who installed yours.

    Cut them flush with an angle grinder, then use a punch and hammer to drive them deeper, patch with concrete patch mix........Rod

  8. #8
    If those are hardened steel anchors, for instance like Hilti makes, it would be a bear to cut them off. On the rare occasion a concrete anchor had to be removed because it wasn't set flush, I, and everyone I saw do this on the jobsite, would try to loosen them by hitting them on the side with a hammer. Then fill it with the patch of your choice. I've used everything from basic mortar to Waterplug. It all depends on what kind of abuse it will have to take.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  9. #9
    Rod just described the 'preferred' process in the material handling world. When we installed or moved conveyors, guard rails, etc, the holes were always drilled deeper than the bolts. When it's time to replace or move the equipment, cut the bolt as close as possible to the concrete and then tap down level with floor. Nothing else needed to be done 99% of the time.

  10. #10
    Quote Originally Posted by John K Jordan View Post
    I cut them off just below flush with an abrasive disk on a 4-1/2" angle grinder then patch the slight depression.

    JKJ
    Winner.

    That's all I've ever done. Bondo works surprisingly well for filling

  11. #11
    The OP's photo is one reason I prefer drop in anchors, remove the bolts & patch the holes. The OP has their work cut out for them. Is there a way to attach a coupling to the stud, & a bolt on the other side then work it back & forth until it breaks? It may or may not work. The worst option is grind them flush.

  12. #12
    Quote Originally Posted by Rod Sheridan View Post
    I always drill the hole deeper than the anchor.

    If you're lucky so did the person who installed yours.

    Cut them flush with an angle grinder, then use a punch and hammer to drive them deeper, patch with concrete patch mix........Rod
    If you are lucky... indeed. Here in the plant, we always drill the holes for wedge anchors at least 1" longer than the anchor itself. That way you can simply pound the anchor flush (or below with a pin punch) if you move things around later. Sometimes this means drilling through the slab if it's only 4-5" thick. It only takes another minute to drill deeper to save you hours in the future.

    But back to the real world. Chances are whomever installed those anchors did not, but it's easy enough to try. Just hit one a few time to see if you the hole is deeper. Don't go caveman on it or you could blow out the concrete below. If it doesn't budge - as others here have said - use a grinder with a cut-off wheel and grind it flush.

  13. #13
    Join Date
    Apr 2018
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    Cambridge Vermont
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    It may not be the cheapest but it would be the quickest, fill them with epoxy. You can get it in a tube so it can be squirted in like caulk. If it was a couple dozen I would use mortar. But that many, that's still a lot of work. To cut costs down you could fill in part of the hole with some cheap caulk and let it set up for a day and then put the epoxy on top of it. Try to pound then in with a hand sledge to see if you can avoid cutting them off flush. If you do cut them off flush wear a respirator or at least make sure you have real good ventilation. When my house was built one of the few things I didn't do was the cement work. The guy used ties made from wire to hold the forms in place. The wire would make a loop around a bar on the outside of the form. Simply twisting the bar snapped the loop but left two steel wires sticking out of the cement. Lots of them. I cut them with a 4 1/2" grinder with a fan blowing the dust away (and no house above me) and it still got dusty.

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